Cost of living in a new city: what equivalent do you need to earn in your new city?

I just thought this was neat.

Are you moving and getting a new job somewhere else? Want to compare what salary you would need in the new town to maintain your lifestyle? Go to payscale.com. You enter your old and new cities, your position name, and your current salary, and using cost of living data, it calculates the minimum salary you need to get in the new city to be equivalent to the old town.

Go here.

Investopedia has a similar site but it breaks down COL into more categories like taxes, housing, and food.